/Engine/Source/Runtime/Engine/Classes/Animation/Skeleton.h
Note that this bonetree can't ever clear up because doing so will corrupt all animation data that was imported based on this If nothing exists, it will build new bone tree
true if success
bool MergeBonesToBoneTree ( const [USkinnedAsset](API\Runtime\Engine\Engine\USkinnedAsset) * InSkinnedAsset, const [TArray](API\Runtime\Core\Containers\TArray)< int32 > & RequiredRefBones )